The invention relates to heat exchangers, in particular for motor vehicles.
It concerns more particularly a heat exchanger of the type comprising a bundle of tubes and of fins, in which the ends of the tubes are introduced into the holes of a manifold plate, as well as a manifold box having an open face delimited by a peripheral rim, and in which heat exchanger the manifold plate is provided with crimping means suitable for coming to bear against the peripheral rim of the manifold box while compressing a sealing gasket.
Heat exchangers of this type are already known, which are used in motor vehicles, in particular in order to cool the engine or heat the passenger compartment.
In known heat exchangers of this type, the manifold plate is usually provided with collars through which the ends of the tubes of the bundle pass.
Distinction is made between two main types of heat exchangers: exchangers of the mechanically assembled type, and exchangers of the brazed type.
In the first case, the ends of the tubes are received in the collars of the manifold plate with the insertion of corresponding collars forming part of the sealing gasket. The collars of the sealing gasket are compressed by widening of the tubes.
In the second case, the ends of the tubes are received directly in the collars of the manifold plate, and are brazed to it.
The sealing between the manifold plate and the manifold box is ensured by the sealing gasket's perimeter, which is received in a peripheral groove of the manifold plate that forms a kind of gutter. This groove receives both the perimeter of the sealing gasket and the manifold box's rim, against which the crimping means of the manifold plate come to bear. These crimping means may be produced, for example, in the form of tongues folded against the rim of the manifold box.
The presence of this peripheral groove has hitherto been indispensable in order to make it possible both to accommodate the perimeter of the sealing gasket, as well as the rim of the manifold box, and to hold this rim during the crimping operation. This is because, without the presence of this groove, the peripheral rim of the manifold box would tend to move inward under the effect of the high pressures which are exerted during the crimping operation.
However, the presence of this groove, which surrounds a generally flat bottom of the manifold plate, increases the space requirement, especially the width requirement, of the heat exchanger. This is because the space requirement of the manifold plate proper is much greater than that of the bundle, which is usually defined by the fins.
In current vehicles, however, the space allocated to the equipment is increasingly limited, and it is found necessary to be able to reduce the space requirement of the heat exchangers, while retaining comparable thermal performance.